GARFT is an enzyme essential in the pathway for de novo synthesis of purines. AG2034 is a novel inhibitor of GARFT. This study will evaluate the safety and dose tolerance of AG2034 when given IV to patients with advanced cancer. The pharmacokinetics and pharmacodynamics for AG2034 using indicator of folate and purine status and cellular retention of drug-metabolites will be studied. Any antitumor effects will be documented. The maximum dose and dose-limiting toxicities will be determined.